Let us learn how connection mode of common anode works. Choose 16 ports on UNO board to connect to the 16 ports of LED Matrix. Configured one port in columns for low level, which make the column of the port selected. Then configure the eight ports in row to display content in the selected column. Delay for a moment. And then select the next column and outputs the corresponding content. This kind of operation to column is called scan. If you want to display the following image of a smiling face, you can display it in 8 columns, and each column is represented by one byte.
